Citrus: A plant genus of the family RUTACEAE. They bear the familiar citrus fruits including oranges, grapefruit, lemons, and limes. There are many hybrids which makes the nomenclature confusing.Citrus sinensis: A plant species of the genus CITRUS, family RUTACEAE that provides the familiar orange fruit which is also a source of orange oil.Closterovirus: A genus of plant viruses in the family CLOSTEROVIRIDAE containing highly flexuous filaments. Some members are important pathogens of crop plants. Natural vectors include APHIDS, whiteflies, and mealybugs. The type species is Beet yellows virus.Hesperidin: A flavanone glycoside found in CITRUS fruit peels.Citrus paradisi: A plant species of the genus CITRUS, family RUTACEAE that produces the familiar grapefruit. There is evidence that grapefruit inhibits CYTOCHROME P-450 CYP3A4, resulting in delayed metabolism and higher blood levels of a variety of drugs.Plant Diseases: Diseases of plants.Rhizobiaceae: A family of gram-negative bacteria which are saprophytes, symbionts, or plant pathogens.Citrus aurantiifolia: A plant species of the genus CITRUS, family RUTACEAE that provides the familiar lime fruit. Its common name of lime is similar to the limetree (TILIA).Fruit: The fleshy or dry ripened ovary of a plant, enclosing the seed or seeds.Poncirus: A plant genus of the family RUTACEAE. Members contain ponfolin, a coumarin (COUMARINS).Flavones: A group of 4-keto-FLAVONOIDS.Limonins: A group of degraded TRITERPENES in which the four terminal carbons of the C17 side chain have been removed, and the remaining portion often forming C17 furans.Xanthomonas axonopodis: A species of gram-negative bacteria in the genus XANTHOMONAS, which causes citrus cankers and black rot in plants.Cyclohexenes: Six-carbon alicyclic hydrocarbons which contain one or more double bonds in the ring. The cyclohexadienes are not aromatic, in contrast to BENZOQUINONES which are sometimes called 2,5-cyclohexadiene-1,4-diones.Oils, Volatile: Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.Xanthomonas: A genus in the family XANTHOMONADACEAE whose cells produce a yellow pigment (Gr. xanthos - yellow). It is pathogenic to plants.Viroids: A group of pathogens comprising the smallest known agents of infectious disease. They are unencapsulated and are capable of replicating autonomously in susceptible cells. Positively identified viroids composed of single-stranded RNA have been isolated from higher plants, but the existence of DNA viroids pathogenic to animals is suspected.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Hemiptera: A large order of insects characterized by having the mouth parts adapted to piercing or sucking. It is comprised of four suborders: HETEROPTERA, Auchenorrhyncha, Sternorrhyncha, and Coleorrhyncha.Monoterpenes: Compounds with a core of 10 carbons generally formed via the mevalonate pathway from the combination of 3,3-dimethylallyl pyrophosphate and isopentenyl pyrophosphate. They are cyclized and oxidized in a variety of ways. Due to the low molecular weight many of them exist in the form of essential oils (OILS, VOLATILE).